Clutter (radar)
Clutter is a term used for unwanted echoes in electronic systems, particularly in reference to radars. Such echoes are typically returned from ground, sea, rain, animals/insects, chaff and atmospheric turbulences, and can cause serious performance issues with radar systems.
Read more about Clutter (radar): Backscatter Coefficient, Clutter or Noise Limited Radar, Volume Clutter, Surface Clutter